The present invention relates to object reference in a virtual shared space and, more particularly, to a technique of automatically putting a reference mark on an object to pay attention to.
A service to provide an online virtual reality world created by three-dimensional computer graphics has recently attracted attention. Each user of the service accesses the virtual reality world by connecting to a host server via a network such as the Internet from a computer having dedicated client software installed therein. In the virtual reality world, the user of the service performs activities by operating an avatar representing the user. For example, through the avatar, the user of the service can look around a streetscape or buildings created in the virtual reality world, perform a business transaction there, or enjoy conversations with other users the user meets.
In the real world, when people have a conversation by referring to something, they often try to let the other person know an object they are referring to with gestures such as pointing. Also in a three-dimensional virtual reality world, the user can indicate a specific object by making the user's avatar take a specific posture or by using reference terms in a message. Such a way of communication does not, however, always function as well as in the real world. This can be, for example, because the users accessing the virtual reality world may see different images from each other when a view of the virtual reality world seen from the avatar of each of the users is displayed on a computer screen of each user.
It is also conceivable to put a mark on an object to be referred to so as to allow the other person to easily identify the object in the virtual reality world. For example, Japanese Patent Application Publication No. 2006-212423 discloses a technique of: designating an object by receiving a command from a user to designate the object; and associating selected information with the object by receiving a command from the user to associate the selected information with the object. By use of this technique, the user designates, for example, a window, associates a reference mark therewith, and also displays a text “caution sniper” near the window. Thus, the user can allow different players to easily identify the window and know associated information.
However, the above technique disclosed in Japanese Patent Application Publication No. 2006-212423 is aimed at object reference in a three-dimensional game in which the same target is set for the player. Thus, it is difficult to effectively utilize the above technique of putting the reference mark in a more versatile three-dimensional virtual reality world in which each person freely performs activities, such as SECOND LIFE® (trademark of Linden Research, Inc.) operated by Linden Lab, Inc. This is because, in the more versatile three-dimensional virtual reality world, an object that one user wishes to focus attention on does not necessarily agree with an object that a different user is interested in, since sense of purpose and background knowledge differ among the users. As a result, all the hard work for putting reference marks can go to waste in some cases, or no reference marks are actually put on what a user is interested in, in other cases.
It is also possible to cope with the problem described above by putting reference marks on each and every object. However, the user has to input a considerable number of commands to put the reference marks. Thus, such a method is not a realistic solution. Moreover, even if a reference mark is put on the object the user is interested in, the user never even notices the reference mark unless the object having the reference mark put thereon is displayed on the computer screen of the user.